Dyed polyurethane threads



United States Patent Ofice 3,518,045 Patented June 30, 1970 3,518,045 DYED POLYURETHANE THREADS Wolfgang Rellensmann, Horst Wieden, Bela von Falkai,

and Alfred Reichle, Dormagen, Germany, assignors to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen,

Germany, a corporation of Germany.

No Drawing. Filed Dec. 8, 1965, Ser. No. 512,518

Claims priority, application 6(tgrmany, Dec. 10, 1964,

Int. 01. 1166 3/24 US. Cl. 8-178 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a process for preparing fast dyed elastomer filaments consisting of segmented polyurethanes. Several processes have recently become known for the production of synthetic, rubbery elastic textile filaments of prominent importance among these materials are the Spandex fibres. For the production of these filaments and fibres, linear and/or slightly branched polyesters or polyethers containing hydroxyl groups are reacted with an excess of aliphatic or aromatic diisocyanates according to the known principle of diisocyanate polyaddition to produce a preadduct having terminal isocyanate groups, and this macrodiisocyanate is then chain lengthened in polyacrylonitrile solvents by means of amino alcohols, diamines, diols, amino carboxylic acids, dihydrazides, hydrazine or simply water to form a segmented polymer. If the resulting solution has a suitable viscosity, it can be formed into rubbery elastic filaments by spinning it according to known processes into a precipitation bath or into a heated shaft in an inert atmosphere, the solvent being removed. The filaments obtained have the usual good textile technological properties such may contain for example known hom'opolymers of the (B-dimethylamino)-ethyl-ester of methacrylic acid so that it is possible to obtain dyeings for example with acid dyestuffs, 1:2-metal-complex dyestufls, disperse-dyestuffs and after-chroming dyestufis. Good dyeability with the same dyestuffs is also shown by elastomer fibres in which,

according to earlier proposals of the applicants, lower molecular weight compounds which are 'bifunctional to the isocyanate groups had been incorporated as so-called co-chain-lengthening agents by an addition process, which chain lengthening agents contain one or more basic groups, usually tertiary amino groups, in the same molecule. In addition, very good dyeings with basic dyestulfs can also be produced on the elastomer filaments and fibres if the fibre-forming polymer contains low molec ular weight compounds having one or more acid groups, in the form of their alkali metal or alkyl ammonium salts, which low molecular weight compounds are bifunctional to the isocyanates and have been incorporated by an addition process.

However, the fastness properties of the dyeings on all these elastomer filaments and fibres are consistently lower than on other synthetic fibres, and this factor limits the use of coloured elastomer fibres; sullicient colour fastness for general purposes can be obtained only by using afterchroming dyestuffs, but after-chroming has an adverse effect on the properties of the filaments, for example the elasticity is reduced by 2 0 to 30%. In addition, incisions and tears on the dyed elastomer filaments indicate that the fibre has only been dyed on the surface and not in depth.

The present invention relates to a process for the production of dyed rubbery elastic filaments and fibres which are completely dyed throughout their thickness and have brilliant colour tones, especially in the blacks, improved colour fastness, such as wet fastness and fastness to perspiration but unchanged textile properties.

The process is characterised in that to a solution in an organic polar solvent of a high molecular weight segmented polyurethane prepared from essentially linear polyhydroxy compounds, diisocyanates, low molecular weight chain lengthening agents and co-chain lengthening agents (i.e. compoundswhich are bifunctional towards isocyanate groups and contain, in the same molecule, one or more basic groups in the form of tertiary nitrogen atoms and/or one or more acid groups in the form of their alkali metal or alkyl ammonium salts), acid or basic dyestuffs soluble in polyacrylonitrile solvents (polar solvents) are added and mixed with said solution in polyacrylonitrile solvents of high molecular weight elastic fibre-forming polymers and subsequently forming the coloured polymer solution into filaments or fibres by known processes.

It is an object of this invention to provide a fast dyed elastic filament from a high molecular segmented polyurethane containing in the segmented structure tertiary amino groups (basic groups) and/or disulfonic acid or disulfimide groups (acid groups) and bound thereto an acid and/or basic dyestuflf.

Especially suitable for use as solvents for the fibreforming polymers are polyacrylonitrile solvents such as dimethylformamide, dimethylacetamide, dimethylsulphoxide and others.

Especially suitable polyhydroxy compounds for the production of the elastic fibre polymers in the process according to the invention are linear or slightly branched polyesters, polyester amides, polyethers, polythioethers and polyacetals which have terminal hydroxyl groups. The melting point of these compounds should preferably be below 60 C. Suitable diisocyanates are p-phenylene diisocyanate, 1:5-naphthylene diisocyanate, 4,4-diphenylmethane diisocyanate, 3:3 dimethyl 4:4'-diphenylmethane diisocyanate, 4:4'-diisocyanate stilbene, 4:4-diisocyanate dibenzyl, mixtures of 2:4- and 2.:6-toluylene diisocyanates and hexamethylene diisocyanate,

Examples of suitable chain lengthening agents are water, glycols, 1:5-naphthylene-bis fl-hydroxyethyl-ether, hydrazine or acid hydrazides such as carbodihydrazide, adipic acid dihydr-azide, or diamines such as piperazine,

ethylene diamine and phenylene die-mines.

Bifunctional cochain-lengthening agents which have proved to be especially advantageous, if acid dyestuffs are used, are diamine and diols as well as dihydrazides which in addition contain one or more tertiary nitrogen atoms, e.g. preferably piperazine derivatives such as N:N-bis (aminoalkyl) piperazines or N:N-bis-(hydroxyalkyl -piperazines.

If basic dyestuffs are used, particularly suitable examples of co-chain-lengthening agents bifunctional towards isocyanates for binding the dyestuff are diamines, diols and dihydrazides which in addition contain one or more H-acidic groups such as sulphonic-acid groups and/or disulphimide-groups in the form of their alkali metal or alkyl ammonium salts; particularly suitable are diaminoaryl-sulphonic-acids such as 4:4'-diaminodiphenyl-2:2'- disulphonic acid, 4:4 diaminodibenzyl-Z:2-disulphonic acid or N sulphobutylethylene diamines, N sulphobutyl hexamethylene diamine, N-sulphobutyl-ethanolamine and N-sulphobutyl-hydrazine.

Agents which are suitable for both acid and basic dyestuffs are mixtures of polymer solutions one solution component of which contains a fibre polymer in which a basic co-chain-lengthening agent has been incorporated by addition whilst the other solution component contains a fibre polymer in which an acid co-chain-lengthener has been incorporated by addition. However, for this purpose it is preferred to use polymers which have been prepared in solution using both acid and basic co-chain lengthening agents together. Also suitable for dyeing with acid or basic dyestuffs are, of course, solutions in which the elastic high polymers have incorporated by addition, co-chain lengthening agents which contain both basic and acid groups of the above mentioned type in one molecule, although in this case the range of variation as regards the ratio of basic to acid groups is greatly limited and is laid down a priori by the amphoteric co-chain-lengthening agent employed.

Suitable dyestuffs for the process according to the invention are any acid dyestuffs soluble in polyacrylonitrile solvents, e.g. the supranols or supramines as well as the basic dyestuffs for example of the series of astrazones or aniline dyes (see, for example, Colour Index 50315; 50415B; 51005).

The dyestuffs are employed in quantities of 0.1 to 10% by weight, preferably 0.3 to 6%, calculated on the fibre polymer.

Filaments and fibres with exceptionally brilliant and deep black tones with excellent fastness to wet and perspiration can be obtained according to the invention by adding black aniline dyes such as Nigrosin Base GB (Colour Index 50415B) to the polymer solution whose elastic fibre polymer carries the above mentioned H- acidic groups.

To carry out the process, the described elastomer solutions having viscosities of 100 to 1600 poises at 20 C, preferably 60 to 1000 poises at 20 C., are mixed w th the above mentioned dyestuffs in a vessel equipped with stirrer and are then formed into multifilaments according to the general principles of solution spinning processes.

According to a preferred method, the dyestulf dissolved in polyacrylonitrile solvents is added to the elastomer solution in a mixing apparatus immediately before the spinning process, especially on account of the fact that when the dye bases are employed, the spinning solution may undergo a change in viscosity after prolonged standing.

Before they are finally used, the threads produced by the process according to the invention should be washed once at 30 C. with a surface active agent, for example an alkyl sulphonate (alkyl group C -C g./l.) to remove any dyestutf adsorbed on the surface and to impart the full fastness properties to the elastomer. Other Washing and wetting agents may also be employed, for

example Marseilles soap, Turkey red oil and nonionogenic synthetic wetting agents based on ethoxylated alkyl phenols.

This method of spin dyeing circumvents the otherwise necessary pretreatments, for example for removing the dressing agents which greatly complicate dyeing in a dye bath, tedious vat dyeing processes and after-treatments for fixing the dyestuffs.

The following examples serve to explain the process of the invention.

EXAMPLE 1 250 parts of polyester (OH number 56) of adipic acid, hexane-1:6-diol and 2:2 dimethylpropane 1:3 diol (molar ratio 10:6.6:3.5) are melted at C., until clear, reacted with stirring, with 71.9 parts of 4:4'-diphenylrnethane diisocyanate and kept at 75 to C. for 45 minutes.

The molten mixture of the addition product of polyesterdiisocyanate and the free diisocyanate is intensively mixed with 863 parts of dimethylformamide which con tains 1.25 parts of N:N'-bis-(fl-hydroxyethyl)-piperazine and 2.55 parts of water in solution. The reaction temperature is adjusted to 50 C. After 5 to 6 hours, the solution has the necessary viscosity for spinning. A further 0.8 part of water is stirred into the spinning solution and left to cool to room tempertaure. The solution, which has a solids content of 27% at a viscosity of 1000 poises, is mixed with Supranol Blue BL (C.I., Acid Blue 59; 50315) in a quantity of 0.5% based on the polymer, at 35 C. in a vessel equipped with stirrer, and the evacuated solution is spun through a multi-aperture spinneret of aperture diameter p. into a shaft which is heated to 200 C., and air preheated to 180 C. is blown over the nozzle of the spinneret. The filaments leaving the spinneret are drawn off over rollers, treated with an oily dressing and wound at a rate of 300 m./min. The brilliant, deep blue threads have good colour fastness after they have been washed for 30 minutes at 30 C. with 5 g./l. of a C -C alkyl sulphonate.

EXAMPLE 2 In a manner analogous to Example 1, a 27% elastomer solution in dimethylformamide of 250 parts of polyester [(OH number 56) of adipic acid, hexane-1:6-diol and 2:2 dimethylpropane-1:3-diol. molar ratio 10:65:35], 71.9 parts of 4:4-diphenylmethane diisocyanate, 3.5 parts of water and 5 parts of 4:4'-diaminodiphenyl-2:2'-disulphonic acid lithium (acid co-chain lengthening agent) and 4.8 parts of titanium dioxide having a viscosity of 1100 poises is prepared and is stirred with 3% Astrazon Black WRL based on the quantity of polymer, stirred and spun into multi-filament endless threads. The deep black threads obtained have good colour fastness properties after a washing in 5 g./l. of a C -C alkyl sulphonate.

EXAMPLE 3 A solution prepared according to Example 2 is introduced into a mixing apparatus into which a 35% solution of Nigrosin Base GB (Cl. Solvent Black 7; 50415B) in dimethy]-formamide is injected at the same time in a quantity such that the solution leaving the mixing apparatus and flowing into the spinneret has a dyestuff content of 3% based on the polymer. The resulting black coloured solution is immediately spun into multi-filament endless threads after mixing as in Example 1. The deep black threads Washed with 5 g./l. of a C to C alkyl sulphonate for 30 minutes at 30 C. have a brilliant black tone and excellent colour fastness (see Table 1).

EXAMPLE 4 A 27% elastomer solution in dimethylformamide is prepared in a manner analogous to Example 1 from 250 parts of polyester [(OH number 56) of :adipic acid, hexanediol and 2:2 dimethylpropane-1:3-diol, molar ratio 10:6.6:3.51], 79.7 parts of 4:4-diphenylmethane diisocyanate, 40 parts of 1:5 naphylene-bis-p-hydroxyethyl ether and 5 parts of N:N'-bis-;S-hydroxyethyl piperazine.

The solution, which has a viscosity of 150 poises at 20 C., is stirred with 0.5%, based on the polymer, of Supramine Red GG (C.I. Acid range 19; 14690), ventilated and spun through a r'nulti-aperture spinneret into a water bath at 60 C. containing dimethylformamide, to form a multi-filament thread which is dried in air at 50 C. and wound. The threads obtained are washed for 30 minutes at 30 C. in 5 grams/liter of a C to C alkyl sulphonate and dried. The brilliant deep red threads have good fastness properties.

EXAMPLE 5 An elastomer solution of 250 parts of polyester, 62.5 parts of 4:4'-diphenylmethane diisocyanate, 78 parts of chlorobenzene, 6.6 parts of hydrazine hydrate and 2.5 parts of N-aminoethyl-aminobutane 4 sulphonic acid lithium (acid co-chain-lengthening agent) is prepared at a concentration of 27% in dimethylformamide in a manner analogous to Example 1.

The solution, which has a viscosity of 200 poises, is stirred with 0.3% Astrazon Yellow 7 G11 (01. basic Yellow 21); based on the quantity of solids, stirred, and spun to multi-filament threads in a manner analogous to Example 4. After a washing as in Example 4, the brilliant yellow dyed threads have good fastness properties.

EXAMPLE 6 A 27% elastomer solution in dimethylformamide is prepared in a manner analogous to Example 1 from 250 parts of polyester, 71.9 parts of 4:4'-diphenylmethane diisocyanate, 2.5 parts of water and 2.5 parts of 4:4'-diaminodiphenyl-disulphonic acid lithium (acid-co-chain lengthening agent), and a second elastomer solution is prepared from 250 parts of polyester, 71.9 parts of 4:4- diphenylmethane diisocyanate, 1.9 parts of water and 7.5 parts of; N:N'-bis-p-hydroxyethyl piperazine (basic cochain-lengthening agent). The two 27% solutions of elastomers in dimethylformamide are thoroughly mixed in the ratio of 2:1 and the mixture of solutions is then divided into two parts A and B. Into 1 part A of the solution is stirred 0.3% Astrazon Blue BG (C.I. Basic Blue 3; 51005), and into the other part B is stirred 0.3% Supranol Blue PL (C.I. Acid Blue 59; 50315).

The filaments prepared from these solutions in a manner analogous to Example 4 have brilliant blue dyeing with good fastness properties after the washing according to Example 4.

EXAMPLE 7 A 27% elastomer solution in dimethylformarnide is prepared from 250 parts of polyester (see Example 1), 71.9 parts of 4:4'-diphenylmethane diisocyanate, 1.9 parts of water, 2.5 parts of 4:4-diaminodiphenyl-2:2-disulphoric acid lithium (acid co-chain-lengthening agent) and 5 parts of N:N-bis-fi-hydroxyethylpiperazine (basic co-chain-lengthening agent). The solution, which has a viscosity of 1000 poises at C., is divided into two parts A and B.

Part A is stirred together with 0.5% of Astrazon Red RL (C.I. Basic Red and part B is stirredtogether with 0.5 of Supramine Red GG (C.I. Acid Orange 19; 14690) based on the amount of solids.

Both solutions are spun in a manner analogous to Example 1 into endless, multi-filament threads which, after a washing according to Example 1, have a deep brilliant red dyeing with good fastness properties.

EXAMPLE 8 (Example for comparison) A solution prepared according to Example 1 but without the addition of dyestuffs is spun as in Example 1 to endless, multi-filament threads and washed as in Example 1. The washed threads are then dyed in a dye bath with 6% Supranol Black V1 (0.1. Acid Black 26; 27070) at boiling temperature for 60 minutes. After drying, the fastness properties of the deep black threads are not quite satisfactory.

Tests for fastness The coloured elastomer threads produced according to Examples 1 to 8 were subjected to various fastness tests and judged. The tests are in accordance with the DIN regulations.

1 The factor estimated was the running of the dyeing inawoven fabric of polycaprolactam threads; the figures denote: 5 excellent, 4 very good, 3 good to satisfactory, 2 not adequate, 1 very poor.

2 5 g./l. Marseilles soap, 30 minutes at 40 C.

8 5 g./l. Marseilles soap+2 g./1. sodium carbonate, 30 minutes at 60 C.

4 5 g./l. Marseilles soap+2 g./1. sodium carbonate at boiling temperature for 30 minutes.

What we claim is:

1. A spinning solution for the production of spindyed fibers of segmented polyurethane elastomers, said spinning solution having a viscosity of to 1600 poises at 20 C. and comprising a polar organic solvent; a segmented polyurethane elastomer prepared by reaction of an isocyanate terminated polyurethane prepolymer with chain-extending agents containing one or more groups selected from the group consisting of tertiary amino groups, disulfonic acid groups, and disulfimide groups; and 0.1 to 10% by weight based on the weight of the polyurethane elastomer of a basic or acidic dyestufi, said dyestuif being soluble in said polar organic solvent.

2. The spinning solution of claim 1, wherein said polar organic solvent is dimethylformamide.

3. The spinning solution of claim 1 wherein said segmented polyurethane elastomer has been prepared by reaction of (a) an isocyanate terminated polyurethane prepolymer from an aromatic diisocyanate and a polyester having terminal hydroxyl groups and a melting point of below 60 C. with (b) a chain-extending agent selected from the group consisting of a N,N-bis-(hydroxyalkyl)- piperazine, a N,N-bis-(aminoalkyl)-piperazine and a diamino-aryl-disulfonic acid.

4. A method for preparing the spinning solution of claim 1 which comprises a mixing (a) 0.1 to 10% by weight based on the weight of segmented polyurethane elastomer of a basic or acidic dyestuff being soluble in a polar organic solvent and (b) a solution of segmented polyurethane elastomer prepared by reaction of an isocyanate terminated polyurethane prepolymer with chainextending agents containing one or more groups selected from the group consisting of tertiary amino groups, disulfonic acid groups, and disulfimide groups in a polar organic solvent, said spinning solution having a viscosity of 100 to 1600 poises at 20 C.

5. The method of claim 4 wherein said chain-extending agent is N,N'-bis-(B-hydroxyethyl)-piperazine.

6. The method of claim 5, wherein said chain-extending agent is 4,4-diaminodiphenyl-2,2-disulfonic acid.

7. Spinning solution of claim 1 wherein said chainextending agent contains a tertiary amino group and said dyestuff is acidic.

8. Spinning solution of claim 1 wherein said chainextending agent contains at least one disulfonic acid group or disulfimide group and said dyestulf is basic.

9. A spin-dyed elastomer fiber consisting of 99.7%

and'forrned by spinning the solution of claim 3.

7 8 to 94% by Weight of a segmented polyurethane elastomer 4 FOREIGN PATENTS and'0.3% t0'6%- by weight of a basic or acidic dyestulf 904,459 8/1962, Great Britain NORMAN G. TORCHIN, Primary'Examiner References Cited 5 J. E. CALLAGHAN, Assistant Examiner UNITED STATES PATENTS 3,294,752 12/1966 Wilkinson 26077.5 Uls. C1.X. 3,376,264 4/1968 Wieden 260-77.5 3,377,308 4/1968 Oertel et al. 264205 2 2605775 

